Adding upstream version 1:115.7.0.upstream/1%115.7.0upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 580 insertions, 0 deletions

diff --git a/js/src/wasm/WasmJS.h b/js/src/wasm/WasmJS.h
new file mode 100644
index 0000000000..53de0f2962
--- /dev/null
+++ b/js/src/wasm/WasmJS.h
@@ -0,0 +1,580 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: set ts=8 sts=2 et sw=2 tw=80:
+ *
+ * Copyright 2016 Mozilla Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef wasm_js_h
+#define wasm_js_h
+
+#include "mozilla/HashTable.h"  // DefaultHasher
+#include "mozilla/Maybe.h"      // mozilla::Maybe
+
+#include <stdint.h>  // int32_t, int64_t, uint32_t
+
+#include "gc/Barrier.h"        // HeapPtr
+#include "gc/ZoneAllocator.h"  // ZoneAllocPolicy
+#include "js/AllocPolicy.h"    // SystemAllocPolicy
+#include "js/Class.h"          // JSClassOps, ClassSpec
+#include "js/GCHashTable.h"    // GCHashMap, GCHashSet
+#include "js/GCVector.h"       // GCVector
+#include "js/PropertySpec.h"   // JSPropertySpec, JSFunctionSpec
+#include "js/RootingAPI.h"     // StableCellHasher
+#include "js/SweepingAPI.h"    // JS::WeakCache
+#include "js/TypeDecls.h"  // HandleValue, HandleObject, MutableHandleObject, MutableHandleFunction
+#include "js/Vector.h"  // JS::Vector
+#include "js/WasmFeatures.h"
+#include "vm/JSFunction.h"    // JSFunction
+#include "vm/NativeObject.h"  // NativeObject
+#include "wasm/WasmCodegenTypes.h"
+#include "wasm/WasmConstants.h"
+#include "wasm/WasmException.h"
+#include "wasm/WasmExprType.h"
+#include "wasm/WasmMemory.h"
+#include "wasm/WasmModuleTypes.h"
+#include "wasm/WasmTypeDecls.h"
+#include "wasm/WasmValType.h"
+#include "wasm/WasmValue.h"
+
+class JSObject;
+class JSTracer;
+struct JSContext;
+
+namespace JS {
+class CallArgs;
+class Value;
+}  // namespace JS
+
+namespace js {
+
+class ArrayBufferObject;
+class ArrayBufferObjectMaybeShared;
+class JSStringBuilder;
+class TypedArrayObject;
+class WasmFunctionScope;
+class WasmInstanceScope;
+class WasmSharedArrayRawBuffer;
+
+namespace wasm {
+
+struct ImportValues;
+
+// Return whether WebAssembly can in principle be compiled on this platform (ie
+// combination of hardware and OS), assuming at least one of the compilers that
+// supports the platform is not disabled by other settings.
+//
+// This predicate must be checked and must be true to call any of the top-level
+// wasm eval/compile methods.
+
+bool HasPlatformSupport(JSContext* cx);
+
+// Return whether WebAssembly is supported on this platform. This determines
+// whether the WebAssembly object is exposed to JS in this context / realm and
+//
+// It does *not* guarantee that a compiler is actually available; that has to be
+// checked separately, as it is sometimes run-time variant, depending on whether
+// a debugger has been created or not.
+
+bool HasSupport(JSContext* cx);
+
+// Predicates for compiler availability.
+//
+// These three predicates together select zero or one baseline compiler and zero
+// or one optimizing compiler, based on: what's compiled into the executable,
+// what's supported on the current platform, what's selected by options, and the
+// current run-time environment.  As it is possible for the computed values to
+// change (when a value changes in about:config or the debugger pane is shown or
+// hidden), it is inadvisable to cache these values in such a way that they
+// could become invalid.  Generally it is cheap always to recompute them.
+
+bool BaselineAvailable(JSContext* cx);
+bool IonAvailable(JSContext* cx);
+
+// Test all three.
+
+bool AnyCompilerAvailable(JSContext* cx);
+
+// Asm.JS is translated to wasm and then compiled using the wasm optimizing
+// compiler; test whether this compiler is available.
+
+bool WasmCompilerForAsmJSAvailable(JSContext* cx);
+
+// Predicates for white-box compiler disablement testing.
+//
+// These predicates determine whether the optimizing compilers were disabled by
+// features that are enabled at compile-time or run-time.  They do not consider
+// the hardware platform on whether other compilers are enabled.
+//
+// If `reason` is not null then it is populated with a string that describes
+// the specific features that disable the compiler.
+//
+// Returns false on OOM (which happens only when a reason is requested),
+// otherwise true, with the result in `*isDisabled` and optionally the reason in
+// `*reason`.
+
+bool BaselineDisabledByFeatures(JSContext* cx, bool* isDisabled,
+                                JSStringBuilder* reason = nullptr);
+bool IonDisabledByFeatures(JSContext* cx, bool* isDisabled,
+                           JSStringBuilder* reason = nullptr);
+
+// Predicates for feature availability.
+//
+// The following predicates check whether particular wasm features are enabled,
+// and for each, whether at least one compiler is (currently) available that
+// supports the feature.
+
+// Streaming compilation.
+bool StreamingCompilationAvailable(JSContext* cx);
+
+// Caching of optimized code.  Implies both streaming compilation and an
+// optimizing compiler tier.
+bool CodeCachingAvailable(JSContext* cx);
+
+// Shared memory and atomics.
+bool ThreadsAvailable(JSContext* cx);
+
+#define WASM_FEATURE(NAME, ...) bool NAME##Available(JSContext* cx);
+JS_FOR_WASM_FEATURES(WASM_FEATURE, WASM_FEATURE, WASM_FEATURE)
+#undef WASM_FEATURE
+
+// SIMD operations.
+bool SimdAvailable(JSContext* cx);
+
+// Privileged content that can access experimental intrinsics
+bool IsSimdPrivilegedContext(JSContext* cx);
+
+#if defined(ENABLE_WASM_SIMD) && defined(DEBUG)
+// Report the result of a Simd simplification to the testing infrastructure.
+void ReportSimdAnalysis(const char* data);
+#endif
+
+// Returns true if WebAssembly as configured by compile-time flags and run-time
+// options can support try/catch, throw, rethrow, and branch_on_exn (evolving).
+bool ExceptionsAvailable(JSContext* cx);
+
+// Compiles the given binary wasm module given the ArrayBufferObject
+// and links the module's imports with the given import object.
+
+[[nodiscard]] bool Eval(JSContext* cx, Handle<TypedArrayObject*> code,
+                        HandleObject importObj,
+                        MutableHandle<WasmInstanceObject*> instanceObj);
+
+// Extracts the various imports from the given import object into the given
+// ImportValues structure while checking the imports against the given module.
+// The resulting structure can be passed to WasmModule::instantiate.
+
+struct ImportValues;
+[[nodiscard]] bool GetImports(JSContext* cx, const Module& module,
+                              HandleObject importObj, ImportValues* imports);
+
+// For testing cross-process (de)serialization, this pair of functions are
+// responsible for, in the child process, compiling the given wasm bytecode
+// to a wasm::Module that is serialized into the given byte array, and, in
+// the parent process, deserializing the given byte array into a
+// WebAssembly.Module object.
+
+[[nodiscard]] bool CompileAndSerialize(JSContext* cx,
+                                       const ShareableBytes& bytecode,
+                                       Bytes* serialized);
+
+[[nodiscard]] bool DeserializeModule(JSContext* cx, const Bytes& serialized,
+                                     MutableHandleObject module);
+
+// A WebAssembly "Exported Function" is the spec name for the JS function
+// objects created to wrap wasm functions. This predicate returns false
+// for asm.js functions which are semantically just normal JS functions
+// (even if they are implemented via wasm under the hood). The accessor
+// functions for extracting the instance and func-index of a wasm function
+// can be used for both wasm and asm.js, however.
+
+bool IsWasmExportedFunction(JSFunction* fun);
+
+Instance& ExportedFunctionToInstance(JSFunction* fun);
+WasmInstanceObject* ExportedFunctionToInstanceObject(JSFunction* fun);
+uint32_t ExportedFunctionToFuncIndex(JSFunction* fun);
+
+bool IsSharedWasmMemoryObject(JSObject* obj);
+
+}  // namespace wasm
+
+// The class of WebAssembly.Module. Each WasmModuleObject owns a
+// wasm::Module. These objects are used both as content-facing JS objects and as
+// internal implementation details of asm.js.
+
+class WasmModuleObject : public NativeObject {
+  static const unsigned MODULE_SLOT = 0;
+  static const JSClassOps classOps_;
+  static const ClassSpec classSpec_;
+  static void finalize(JS::GCContext* gcx, JSObject* obj);
+  static bool imports(JSContext* cx, unsigned argc, Value* vp);
+  static bool exports(JSContext* cx, unsigned argc, Value* vp);
+  static bool customSections(JSContext* cx, unsigned argc, Value* vp);
+
+ public:
+  static const unsigned RESERVED_SLOTS = 1;
+  static const JSClass class_;
+  static const JSClass& protoClass_;
+  static const JSPropertySpec properties[];
+  static const JSFunctionSpec methods[];
+  static const JSFunctionSpec static_methods[];
+  static bool construct(JSContext*, unsigned, Value*);
+
+  static WasmModuleObject* create(JSContext* cx, const wasm::Module& module,
+                                  HandleObject proto);
+  const wasm::Module& module() const;
+};
+
+// The class of WebAssembly.Global.  This wraps a storage location, and there is
+// a per-agent one-to-one relationship between the WasmGlobalObject and the
+// storage location (the Cell) it wraps: if a module re-exports an imported
+// global, the imported and exported WasmGlobalObjects are the same, and if a
+// module exports a global twice, the two exported WasmGlobalObjects are the
+// same.
+
+// TODO/AnyRef-boxing: With boxed immediates and strings, JSObject* is no longer
+// the most appropriate representation for Cell::anyref.
+STATIC_ASSERT_ANYREF_IS_JSOBJECT;
+
+class WasmGlobalObject : public NativeObject {
+  static const unsigned MUTABLE_SLOT = 0;
+  static const unsigned VAL_SLOT = 1;
+
+  static const JSClassOps classOps_;
+  static const ClassSpec classSpec_;
+  static void finalize(JS::GCContext* gcx, JSObject* obj);
+  static void trace(JSTracer* trc, JSObject* obj);
+
+  static bool typeImpl(JSContext* cx, const CallArgs& args);
+  static bool type(JSContext* cx, unsigned argc, Value* vp);
+
+  static bool valueGetterImpl(JSContext* cx, const CallArgs& args);
+  static bool valueGetter(JSContext* cx, unsigned argc, Value* vp);
+  static bool valueSetterImpl(JSContext* cx, const CallArgs& args);
+  static bool valueSetter(JSContext* cx, unsigned argc, Value* vp);
+
+ public:
+  static const unsigned RESERVED_SLOTS = 2;
+  static const JSClass class_;
+  static const JSClass& protoClass_;
+  static const JSPropertySpec properties[];
+  static const JSFunctionSpec methods[];
+  static const JSFunctionSpec static_methods[];
+  static bool construct(JSContext*, unsigned, Value*);
+
+  static WasmGlobalObject* create(JSContext* cx, wasm::HandleVal value,
+                                  bool isMutable, HandleObject proto);
+  bool isNewborn() { return getReservedSlot(VAL_SLOT).isUndefined(); }
+
+  bool isMutable() const;
+  wasm::ValType type() const;
+  wasm::GCPtrVal& val() const;
+};
+
+// The class of WebAssembly.Instance. Each WasmInstanceObject owns a
+// wasm::Instance. These objects are used both as content-facing JS objects and
+// as internal implementation details of asm.js.
+
+class WasmInstanceObject : public NativeObject {
+  static const unsigned INSTANCE_SLOT = 0;
+  static const unsigned EXPORTS_OBJ_SLOT = 1;
+  static const unsigned EXPORTS_SLOT = 2;
+  static const unsigned SCOPES_SLOT = 3;
+  static const unsigned INSTANCE_SCOPE_SLOT = 4;
+  static const unsigned GLOBALS_SLOT = 5;
+
+  static const JSClassOps classOps_;
+  static const ClassSpec classSpec_;
+  static bool exportsGetterImpl(JSContext* cx, const CallArgs& args);
+  static bool exportsGetter(JSContext* cx, unsigned argc, Value* vp);
+  bool isNewborn() const;
+  static void finalize(JS::GCContext* gcx, JSObject* obj);
+  static void trace(JSTracer* trc, JSObject* obj);
+
+  // ExportMap maps from function index to exported function object.
+  // This allows the instance to lazily create exported function
+  // objects on demand (instead up-front for all table elements) while
+  // correctly preserving observable function object identity.
+  using ExportMap = GCHashMap<uint32_t, HeapPtr<JSFunction*>,
+                              DefaultHasher<uint32_t>, CellAllocPolicy>;
+  ExportMap& exports() const;
+
+  // See the definition inside WasmJS.cpp.
+  class UnspecifiedScopeMap;
+  UnspecifiedScopeMap& scopes() const;
+
+ public:
+  static const unsigned RESERVED_SLOTS = 6;
+  static const JSClass class_;
+  static const JSClass& protoClass_;
+  static const JSPropertySpec properties[];
+  static const JSFunctionSpec methods[];
+  static const JSFunctionSpec static_methods[];
+  static bool construct(JSContext*, unsigned, Value*);
+
+  static WasmInstanceObject* create(
+      JSContext* cx, const RefPtr<const wasm::Code>& code,
+      const wasm::DataSegmentVector& dataSegments,
+      const wasm::ElemSegmentVector& elemSegments, uint32_t instanceDataLength,
+      Handle<WasmMemoryObject*> memory,
+      Vector<RefPtr<wasm::Table>, 0, SystemAllocPolicy>&& tables,
+      const JSObjectVector& funcImports, const wasm::GlobalDescVector& globals,
+      const wasm::ValVector& globalImportValues,
+      const WasmGlobalObjectVector& globalObjs,
+      const WasmTagObjectVector& tagObjs, HandleObject proto,
+      UniquePtr<wasm::DebugState> maybeDebug);
+  void initExportsObj(JSObject& exportsObj);
+
+  wasm::Instance& instance() const;
+  JSObject& exportsObj() const;
+
+  [[nodiscard]] static bool getExportedFunction(
+      JSContext* cx, Handle<WasmInstanceObject*> instanceObj,
+      uint32_t funcIndex, MutableHandleFunction fun);
+
+  const wasm::CodeRange& getExportedFunctionCodeRange(JSFunction* fun,
+                                                      wasm::Tier tier);
+
+  static WasmInstanceScope* getScope(JSContext* cx,
+                                     Handle<WasmInstanceObject*> instanceObj);
+  static WasmFunctionScope* getFunctionScope(
+      JSContext* cx, Handle<WasmInstanceObject*> instanceObj,
+      uint32_t funcIndex);
+
+  using GlobalObjectVector =
+      GCVector<HeapPtr<WasmGlobalObject*>, 0, CellAllocPolicy>;
+  GlobalObjectVector& indirectGlobals() const;
+};
+
+// The class of WebAssembly.Memory. A WasmMemoryObject references an ArrayBuffer
+// or SharedArrayBuffer object which owns the actual memory.
+
+class WasmMemoryObject : public NativeObject {
+  static const unsigned BUFFER_SLOT = 0;
+  static const unsigned OBSERVERS_SLOT = 1;
+  static const unsigned ISHUGE_SLOT = 2;
+  static const JSClassOps classOps_;
+  static const ClassSpec classSpec_;
+  static void finalize(JS::GCContext* gcx, JSObject* obj);
+  static bool bufferGetterImpl(JSContext* cx, const CallArgs& args);
+  static bool bufferGetter(JSContext* cx, unsigned argc, Value* vp);
+  static bool typeImpl(JSContext* cx, const CallArgs& args);
+  static bool type(JSContext* cx, unsigned argc, Value* vp);
+  static bool growImpl(JSContext* cx, const CallArgs& args);
+  static bool grow(JSContext* cx, unsigned argc, Value* vp);
+  static bool discardImpl(JSContext* cx, const CallArgs& args);
+  static bool discard(JSContext* cx, unsigned argc, Value* vp);
+  static uint64_t growShared(Handle<WasmMemoryObject*> memory, uint64_t delta);
+
+  using InstanceSet = JS::WeakCache<GCHashSet<
+      WeakHeapPtr<WasmInstanceObject*>,
+      StableCellHasher<WeakHeapPtr<WasmInstanceObject*>>, CellAllocPolicy>>;
+  bool hasObservers() const;
+  InstanceSet& observers() const;
+  InstanceSet* getOrCreateObservers(JSContext* cx);
+
+ public:
+  static const unsigned RESERVED_SLOTS = 3;
+  static const JSClass class_;
+  static const JSClass& protoClass_;
+  static const JSPropertySpec properties[];
+  static const JSFunctionSpec methods[];
+  static const JSFunctionSpec memoryControlMethods[];
+  static const JSFunctionSpec static_methods[];
+  static bool construct(JSContext*, unsigned, Value*);
+
+  static WasmMemoryObject* create(JSContext* cx,
+                                  Handle<ArrayBufferObjectMaybeShared*> buffer,
+                                  bool isHuge, HandleObject proto);
+
+  // `buffer()` returns the current buffer object always.  If the buffer
+  // represents shared memory then `buffer().byteLength()` never changes, and
+  // in particular it may be a smaller value than that returned from
+  // `volatileMemoryLength()` below.
+  //
+  // Generally, you do not want to call `buffer().byteLength()`, but to call
+  // `volatileMemoryLength()`, instead.
+  ArrayBufferObjectMaybeShared& buffer() const;
+
+  // The current length of the memory in bytes. In the case of shared memory,
+  // the length can change at any time.  Also note that this will acquire a lock
+  // for shared memory, so do not call this from a signal handler.
+  size_t volatileMemoryLength() const;
+
+  // The current length of the memory in pages. See the comment for
+  // `volatileMemoryLength` for details on why this is 'volatile'.
+  wasm::Pages volatilePages() const;
+
+  // The maximum length of the memory in pages. This is not 'volatile' in
+  // contrast to the current length, as it cannot change for shared memories.
+  wasm::Pages clampedMaxPages() const;
+  mozilla::Maybe<wasm::Pages> sourceMaxPages() const;
+
+  wasm::IndexType indexType() const;
+  bool isShared() const;
+  bool isHuge() const;
+  bool movingGrowable() const;
+  size_t boundsCheckLimit() const;
+
+  // If isShared() is true then obtain the underlying buffer object.
+  WasmSharedArrayRawBuffer* sharedArrayRawBuffer() const;
+
+  bool addMovingGrowObserver(JSContext* cx, WasmInstanceObject* instance);
+  static uint64_t grow(Handle<WasmMemoryObject*> memory, uint64_t delta,
+                       JSContext* cx);
+  static void discard(Handle<WasmMemoryObject*> memory, uint64_t byteOffset,
+                      uint64_t len, JSContext* cx);
+};
+
+// The class of WebAssembly.Table. A WasmTableObject holds a refcount on a
+// wasm::Table, allowing a Table to be shared between multiple Instances
+// (eventually between multiple threads).
+
+class WasmTableObject : public NativeObject {
+  static const unsigned TABLE_SLOT = 0;
+  static const JSClassOps classOps_;
+  static const ClassSpec classSpec_;
+  bool isNewborn() const;
+  static void finalize(JS::GCContext* gcx, JSObject* obj);
+  static void trace(JSTracer* trc, JSObject* obj);
+  static bool lengthGetterImpl(JSContext* cx, const CallArgs& args);
+  static bool lengthGetter(JSContext* cx, unsigned argc, Value* vp);
+  static bool typeImpl(JSContext* cx, const CallArgs& args);
+  static bool type(JSContext* cx, unsigned argc, Value* vp);
+  static bool getImpl(JSContext* cx, const CallArgs& args);
+  static bool get(JSContext* cx, unsigned argc, Value* vp);
+  static bool setImpl(JSContext* cx, const CallArgs& args);
+  static bool set(JSContext* cx, unsigned argc, Value* vp);
+  static bool growImpl(JSContext* cx, const CallArgs& args);
+  static bool grow(JSContext* cx, unsigned argc, Value* vp);
+
+ public:
+  static const unsigned RESERVED_SLOTS = 1;
+  static const JSClass class_;
+  static const JSClass& protoClass_;
+  static const JSPropertySpec properties[];
+  static const JSFunctionSpec methods[];
+  static const JSFunctionSpec static_methods[];
+  static bool construct(JSContext*, unsigned, Value*);
+
+  // Note that, after creation, a WasmTableObject's table() is not initialized
+  // and must be initialized before use.
+
+  static WasmTableObject* create(JSContext* cx, uint32_t initialLength,
+                                 mozilla::Maybe<uint32_t> maximumLength,
+                                 wasm::RefType tableType, HandleObject proto);
+  wasm::Table& table() const;
+
+  // Perform the standard `ToWebAssemblyValue` coercion on `value` and fill the
+  // range [index, index + length) in the table. Callers are required to ensure
+  // the range is within bounds. Returns false if the coercion failed.
+  bool fillRange(JSContext* cx, uint32_t index, uint32_t length,
+                 HandleValue value) const;
+};
+
+// The class of WebAssembly.Tag. This class is used to track exception tag
+// types for exports and imports.
+
+class WasmTagObject : public NativeObject {
+  static const unsigned TYPE_SLOT = 0;
+
+  static const JSClassOps classOps_;
+  static const ClassSpec classSpec_;
+  static void finalize(JS::GCContext* gcx, JSObject* obj);
+  static bool typeImpl(JSContext* cx, const CallArgs& args);
+  static bool type(JSContext* cx, unsigned argc, Value* vp);
+
+ public:
+  static const unsigned RESERVED_SLOTS = 1;
+  static const JSClass class_;
+  static const JSClass& protoClass_;
+  static const JSPropertySpec properties[];
+  static const JSFunctionSpec methods[];
+  static const JSFunctionSpec static_methods[];
+  static bool construct(JSContext*, unsigned, Value*);
+
+  static WasmTagObject* create(JSContext* cx,
+                               const wasm::SharedTagType& tagType,
+                               HandleObject proto);
+
+  const wasm::TagType* tagType() const;
+  const wasm::ValTypeVector& valueTypes() const;
+  wasm::ResultType resultType() const;
+};
+
+// The class of WebAssembly.Exception. This class is used for
+// representing exceptions thrown from Wasm in JS. (it is also used as
+// the internal representation for exceptions in Wasm)
+
+class WasmExceptionObject : public NativeObject {
+  static const unsigned TAG_SLOT = 0;
+  static const unsigned TYPE_SLOT = 1;
+  static const unsigned DATA_SLOT = 2;
+  static const unsigned STACK_SLOT = 3;
+
+  static const JSClassOps classOps_;
+  static const ClassSpec classSpec_;
+  static void trace(JSTracer* trc, JSObject* obj);
+  static void finalize(JS::GCContext* gcx, JSObject* obj);
+  // Named isMethod instead of is to avoid name conflict.
+  static bool isMethod(JSContext* cx, unsigned argc, Value* vp);
+  static bool isImpl(JSContext* cx, const CallArgs& args);
+  static bool getArg(JSContext* cx, unsigned argc, Value* vp);
+  static bool getArgImpl(JSContext* cx, const CallArgs& args);
+  static bool getStack(JSContext* cx, unsigned argc, Value* vp);
+  static bool getStack_impl(JSContext* cx, const CallArgs& args);
+
+  uint8_t* typedMem() const;
+  [[nodiscard]] bool loadValue(JSContext* cx, size_t offset, wasm::ValType type,
+                               MutableHandleValue vp);
+  [[nodiscard]] bool initValue(JSContext* cx, size_t offset, wasm::ValType type,
+                               HandleValue value);
+
+ public:
+  static const unsigned RESERVED_SLOTS = 4;
+  static const JSClass class_;
+  static const JSClass& protoClass_;
+  static const JSPropertySpec properties[];
+  static const JSFunctionSpec methods[];
+  static const JSFunctionSpec static_methods[];
+  static bool construct(JSContext*, unsigned, Value*);
+
+  static WasmExceptionObject* create(JSContext* cx, Handle<WasmTagObject*> tag,
+                                     HandleObject stack, HandleObject proto);
+  bool isNewborn() const;
+
+  JSObject* stack() const;
+  const wasm::TagType* tagType() const;
+  WasmTagObject& tag() const;
+
+  static size_t offsetOfData() {
+    return NativeObject::getFixedSlotOffset(DATA_SLOT);
+  }
+};
+
+// The class of the WebAssembly global namespace object.
+
+class WasmNamespaceObject : public NativeObject {
+ public:
+  static const JSClass class_;
+
+ private:
+  static const ClassSpec classSpec_;
+};
+
+extern const JSClass WasmFunctionClass;
+
+}  // namespace js
+
+#endif  // wasm_js_h